Data from: Genome-wide markers untangle the green-lizard radiation in the Aegean Sea and support a rare biogeographical pattern

Aim: The Aegean Sea constitutes a major biogeographic barrier between the
European and Asian continents and several models of diversification in the
Aegean have been documented. Here we test three of those models for the
Aegean green-lizards (Lacerta trilineata–pamphylica group): Vicariance vs.
Overland Dispersal vs. Island Stepping-stone Dispersal. We investigate
these hypotheses and complement our knowledge on the impact of the Aegean
Barrier on east Mediterranean taxa. Location: Aegean Sea, east
Mediterranean Taxon: Lacerta lizards Methods: We analysed ddRAD loci
(double-digest restriction-site-associated DNA) to estimate species-trees
under coalescent models and maximum likelihood trees using concatenation.
We performed hierarchical population structure analyses and inferred
ancestral distribution-areas. We also sequenced the complete cytochrome b
gene and produced a time-calibrated mtDNA gene-tree tree to conduct a
critical comparison with previous studies. Results: Aegean green-lizards
diverged into four main groups in parallel during the Late Pliocene with
distributions to the East and West of the Aegean. The Eastern group
includes Lacerta pamphylica and East Aegean L. trilineata, while the
Western group contains the Central Cyclades populations and the remaining
populations of the Balkan Peninsula. The Aegean green-lizards’ ancestor
occurred in Anatolia, while the West lineage ancestor occurred in the
Central Cyclades islands, revealing a dispersal between the two regions.
The radiations of all major green-lizard groups, including
trilineata+pamphylica, occurred in parallel in the Late Pliocene. Main
Conclusions: In contrast to previously suggested biogeographical
hypotheses for the group, based on mtDNA, the Island Stepping-stone
Dispersal scenario is strongly supported. Green lizards offer a rare
paradigm of diversification in the Aegean, where populations largely
expanded their geographical distribution and crossed the Aegean Barrier by
using the central Aegean islands as stepping stones.